Oxygen is often employed to healing of the wounds (e.g., ulcers, abrasions, cuts, sores, etc.). Topical oxygen therapy calls for applying oxygen directly to an open wound. The oxygen dissolves in tissue fluids and improves the oxygen content of the intercellular fluids. Injuries and disorders which may be treated with topical oxygen include osteomylelitis, tendon and cartilage repair, sprains, fractures, burns and scalds, necrotizing fasciitis, pyoderma gangrenosum, refractory ulcers, diabetic foot ulcers and decubitus ulcers (bed sores) as well as cuts, abrasions, and surgically induced wounds or incisions.
There have been several attempts to promote wound healing by supplying oxygen to a wound or regulating the oxygen concentration in the vicinity of a wound.
Oxygen chambers apply oxygen either systemically or topically. In the former, the patient breaths high pressure pure oxygen, and in the latter the entire affected limb is placed in a sealed chamber that features controlled pressure sealing and automatic oxygen regulation control. Not only are such oxygen chambers expensive and difficult to sterilize, they are also cumbersome in that the chamber must be hooked up to an external oxygen tank, limiting the patient's mobility. In addition, in the systemic method of oxygen application, the various organs of the body may be unnecessarily subjected to high levels of oxygen. Such high levels of oxygen present risks of vasoconstriction, toxicity and tissue destruction.
Devices in which oxygen is produced electrochemically and transported across an ion conductive membrane typically depend upon water, which has a relatively high vapor pressure and will evaporate. As water in the membrane evaporates, the membrane loses its ability to effectively conduct ions. Thus, over the course of several days, membranes used in such devices tend to lose their ability to transportions and must either be replaced or re-hydrated. Further, attempting to keep the membrane hydrated can result in complications. For example, the inclusion of a water source to keep the membrane moist can make the device cumbersome, mitigating one of the key benefits of such a device. In addition, the close proximity of water to open wounds causes susceptibility to microbial infection.
Self-contained, portable oxygen concentrating devices, such as the one taught in U.S. Pat. No. 7,429,252, employ an ion conducting membrane that does not need to be constantly humidified to maintain conductivity. The oxygen concentrator in such devices is capable of operating for months, but due to limitations of the primary battery, the device must be replaced after a single use.
Many wound locations, e.g., foot, heel, lower ankle etc., call for devices that are thin and flexible, so that they will not interfere with shoes and such outerwear that are part of an ambulatory patient. Thick end plates (for electrical connection and air and oxygen delivery) often used in electrochemical oxygen generating devices generally do not fulfill this requirement.
Bandages and dressings placed over wounds absorb exudate from the environment and need to be disposed of anywhere between 1-7 days after application, depending on the level of exudate generation. In oxygen producing devices, such as those as described above, the dressing then needs to be disposed, since the absorbent dressing becomes saturated with the wound exudate. The oxygen producing device is expensive to make and disposing of the entire dressing, along with the oxygen-producing device is both economically and environmentally undesirable.
Therefore, there is a need for an oxygen delivery device that can reduce or minimize the aforementioned problems.